Category Archives: Equipment Manuals

Rapid Lipo Battery Discharging and disposal

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Lipo Discharging (dis)assembly line.

These are the steps I use to rapidly discharge my broken LiPOs and prepare them for safe disposal. If you are reading this bear in mind that discharging and charging lipos is always risky and require that these be done in a safe place, preferably outdoors with no combustible material nearby.

Lipos are not known to explode but they can generate a lot of heat, smoke and yes sometimes a bit of fire. So place the lipos in a non flammable material like a lipo sack, metal box or, in my case, on top of some ceramic or rock.

There are two common ways to skin this cat:  a) Use a discharger exclusively or b) Use a discharger and some bulbs.  If you want to use the discharger exclusively go to step 1 and jump to step 3. I like the combination since it allows me to discharge different sized batteries at the same time.

1) First bring down total battery voltage to 3v (or less) per cell using a discharger.  This assumes you have a 12v halogen bulb  which will be used to do most of the discharging.  On the other hand, if you will be using a discharger exclusively set the discharge rate at 1C of your LiPO and discharge to the lowest voltage then jump to step 3.

2) Rapid Discharge with a target of 3-4V for the entire pack using halogen bulbs. I use Two (2) 12v 50watt halogen lamps in parallel as the primary and rapid discharger. The pair generates between 8.3A-9.4A of pull. Obviously for  5S and above the bulbs needs to be placed in series (with optional parallel) to accommodate the high voltage.

The 8.3A rate brings a 4S with 12v charge to 3-4v in about 30minutes. Once the bulbs show no light whatsoever, let it stay that way for at least 5 minutes before removing the pack. The halogen lamps are very hot so be careful.

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High discharge rate will almost always result in a puffed pack.

Note that because of the high discharge rate  and below minimum voltage this process induces on the lipos, they will almost always puff.

3) Drip Discharge on last Vs.  After reaching use a charger to discharge at a lower amp. Set the charger to use NiCd (LiPo has a min termination voltage of 3V so it won’t do) and set to DISCHARGE at 1A without attaching the balancing cable. Set the target voltage to the minimum allowed by the charger, in the case of the Turnigy Reaktor its 0.10V. Discharge.

4) Set the second cycle using the charger to half an Amp (0.5A). This will be quick. And will bring the voltage to around 2V after a 3-5 minute pack rest.

5) 3rd cycle we use 0.2A discharge rate. This will take a few minutes and bring the voltage to about 1.5v. Once done make the pack rest for 3-5 minutes.

6) 4th onwards cycle set the discharger to 0.10A (the lowest setting) and discharge. This will take some time (8-10minutes) and is designed to really squeeze most of the remaining juice out of the pack. Let the pack rest for 5 minutes. After rest, it will bounce back to about 1.5v-2v. Do this same same (step #6) 3 to 5 more times making sure to make the pack rest for 5 minutes per discharge. Each cycle will be quicker than the previous one as the chemicals in the pack loses its capacity to regenerate charge.

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1.5v-1.8v good enough terminal voltage for disposal

7) Repeat until 1.5V is reached.  After at least 3 cycles of step #6 the packs will have a voltage of about 1.5v.  Wait for 15minutes and verify that the voltage is steady at 1.5v. If the pack goes beyond this after this longer rest period, discharge it using step #6 a couple of times.

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Cut leads prior to being shorted.

8) Cut off charging lead. At 1.5v the battery is basically dead but still has residual charge. You can reuse the red and black charging wires and plugs by cutting off the wires leaving just enough to short the battery. In my case I also cut off the balancer wire. After cutting the charging wires, use a pair of long nose pliers to expose a bit of both wires and twist them together to short the battery.

9) Safe store for  a day.  Tape the exposed lead and balancer wires and place in a secure place with no flammable material.  It will take 2-12 hours for the residual charge to finally zero out depending on the battery’s capacity.  In my experience a 3S 2200mah charge was completely depleted after 3 hours, a 4S 5000mah about 6 hours, leaving me with just inert material. This means I get to throw these tomorrow with the rest of the trash.

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The Magnificent 7. Goodbye amigos! Thanks for the fun and memories!

Turnigy Reaktor 250W 10A Charger Balancer Rocks! (so far!)

If you’re reading this and just started with the hobby, let me give you a piece of advice to save your LiPos and hard-earned money:

  1. Get a good balancer charger and
  2. Do not charge each LiPO cell to the max of 4.2v, charge instead at 4.1v or 4.15v. This will make the lipos last longer — as much as twice the cycles/lifespan.

I’ve had this generic B6AC+ 80watt AC/DC charger for a little over 3 years now, my first one in fact and its seems to work ok, but I noticed that a big percentage of my lipos are puffing up. At first I attributed this to my usage, but with mainly planes used for FPV and not being an aggressive flyer at all, I found this strange.

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Fast forward recently and with about 25 Lipos of varying cell counts and capacities, half of them have puffed, somethings not right! I can’t be the most stupid RC flyer out there!

What really convinced me was when I bought a 3S 2200mah JRPropo battery. After a couple of cycles, the 3rd cell is always 10% higher in charge and often exceeds 4.2v when trying to charge.  No matter how often I discharge and how long I charge it (balanced of course), the first 2 cells can not get the 4.2v full charge.  Checking the battery with  a fellow flyer’s Powerlab 8 v2 showed that the 3rd cell has twice the resistance as the first 2, however unlike my charger the cellpro is trickling charge into the first 2 cells attempting to catch up with the 3rd.  I didn’t complete it though as I had to leave the field.

So bottom line, the charger had to go.  But what to choose? the Powerlab 8? iCharger? Reaktors? I eventually decided to get the Turnigy Reaktor 250w 10A from HK. It’s cheap (< US$50), full featured (it being a copy of the iCharger 106B+) and looks really cool too.  Fortunately, I also found a local supplier of a good power supply (360w) for it:

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So the verdict? this small charger did a lazarus on my LiPO above! after setting the termination voltage at 4.15v (I can’t do this with my old charger).  I proceeded to do balanced charging.

The image below shows the charging several minutes after I started.  This shows cells 1 and 2 catching up to cell 3, which was pared down to 4.15 (it was registering 4.21v at the beginning) by the charger and maintained at that charge all throughout the charging cycle.
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An hour later, I got fully balanced battery charged at 4.15v each cell!

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I’m beginning to really like this charger.. here’s the balanced cells.

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So if you’re thinking of getting a 2-6s charger, this small charger is very capable.  Full-featured, adequate power to handle high C charging and best of all, cheap!

Installing CHDK to a Canon Powershot SX230 SH

I got a used Canon Powershot SX230 SH for only about $70 (brand new this is about $250).. its beat up pretty good but everything works except for the lens cover which doesnt close even if its turned off.. I dont think this is a big issue at all.

A used Canon Powershot SX 230 SH
A used Canon Powershot SX 230 SH (eyes wide open!)

This will be used as the mapping component of my Skywalker rig and which needs to be updated with CHDK for added features relevant for my use.  Here’s the steps on how to do it:

1) Check out  http://chdk.wikia.com

2) Download the Automatic Camera Identifier and Downloader (ACID) to check for the camera’s installed firmware  (mine was 100c) and download the correct CHDK version (http://www.zenoshrdlu.com/acid/acid.html)
chdk

3) UNLOCK the SD card and format it using the camera’s format function

4) remove the SD card and insert into your PC/laptop.

5) copy all the files downloaded in step 2 to the root directory of the SD card.

chdk directory
chdk directory to copy to your formatted SD card

6) Remove the SD card, LOCK it, then insert into the camera.  Don’t worry CHDK will just ignore the LOCKED state of the SC card and will still allow the camera to write to the SD card (if this is UNLOCKED, CHDK will not start on bootup after step 10).

7) Press the “PLAY” button (not the on/off).

8) Press the MENU Key and under the ‘play’ tab, look for “Firmware Update…” and press the “FUNC SET” button.  After the update, you should see a black/empty screen with “No Image” in the middle (which makes sense since we deleted everything).

Canon sx230 firmware update menu
Canon sx230 firmware update menu

9) Press the ‘PLAY’ key briefly, which is the default <ALT> key to bring up the CHDK menu and you should see the CHDK alternate menu.

chdk main menu after pressing 'play'
chdk main menu after pressing ‘play’

10) Set the SD card to autoboot to CHDK, by pressing MENU (after step 9), navigating to ‘Miscellaneous Stuff’->’SD Card’->’Make Card Bootable’ and pressing ‘FUNC SET’.  The camera will now run CHDK even after turning the camera off.

Making chdk run at startup
Making chdk run at startup

 

CHDK successfully set as bootable in the SDcard
CHDK successfully set as bootable in the SDcard

11)  That’s it!   If you want to see the different features of chdk check out http://chdk.wikia.com/wiki/CHDK_User_Manual.   Suggested script to load is the KAP_UAV script available from: http://chdk.wikia.com/wiki/KAP_UAV_Exposure_Control_Script  Good Luck!

Note: the 230SH will ad 217.3 grams to your rig.

Enabling RSSI or Link Quality in MinimOSD with EzUHF Rx and HKPilot32(or Pixhawk)

This is a quick how-to to get the RSSI or LINK quality on your MinimOSD you need the following:

1)  Download MinimOSD Tools and Firmware. Download the MinimOSD configuration tool (CT Tools) and Minimosd ‘extra’ firmware from: https://code.google.com/p/minimosd-extra/

For my setup I download the following files from: https://code.google.com/p/minimosd-extra/downloads/list

CTTools:   CT Tool for MinimOSD Extra 2.3.2.0 Pre Release r727.zip
Firmware: MinimOSD-Extra_Plane_Pre-release_2.4_r719.hex

2) Setup EzUHF Receiver to send RSSI or LINK quality values.  Since you are using a Pixhawk or HKPilot, the setup should be that all the channels goes through channel 1 which is ‘muxed’.  Connect to your EzUHF receiver using a USB cable and open the ImmersionRC Configuration Tool.  Once connected, just set channel 8 to either RSSI or LINK  (only channel 8 will with MinimOSD for now so its pointless experimenting with other channels).  You can use either RSSI or LINK, but I suggest you use LINK as RSSI is all about the signal strength and not the actual quality of the link.  Upload the settings to the receiver.  Here’s how it looks like:

ezhuf rssi setup
ezhuf rssi setup

4)  Do not edit any parameters in APM or MP.  You do not need to change or update any settings in the AP configuration so leave it as is.

5)  Get the maximum and minimum RSSI or LINK PWM values in MinimOSD.  For this next step, both segments of the MinimOSD must be powered or any updates in the configuration you make with the MinimOSD will not be saved. The OSD output end must be powered with 12v and the other end is plugged to your laptop with an FTDI cable.  Like so:

minimosd config setup
minimosd config setup

Use the configuration tool to set up the RSSI values (in Panel 1). Make sure you write the configuration to MinimOSD.  On the main ‘Config’ panel make sure that you’ve set the ‘RSSI Channel’ to Channel 8… AND make sure the RSSI Enable RAW is checked.

minimosd rssi setup
minimosd rssi setup (the RSSI enable raw must be checked to get raw values)

Save the configuration, remove the MinimOSD, plug it into the Pixhawk cable and Vtx/Camera cables and power up your system.  On the OSD screen where you’ve set the RSSI to be, you should see a number.  Take note of this as this is your ‘maximum’ link quality value.   Unplug your transmitter and take note of the value.  This time you should see a smaller number.  This is the minimum link quality value.  For my setup, the highest was 1793 and the lowest was 1056. I just set it to 1800 and 1050 since the OSD is limited to steps of 10.   Now power down the system, disconnect all cables, connect 12v power source to the MinimOSD and plug back the MinimOSD to your laptop.

6) Update the MinimOSD PWM Min and Max RSSI Values.  Finally,  fire up the MinimOSD CTools again and change the Minimum and Maximum RSSI values to the one you got in step 5.  Also set uncheck the ‘RSSI Enable Raw’ so you can see the values in percentage format. Save the configuration and test.

Spektrum DX6i + EzUHF Receiver + HKPilot32 (aka PixHawk) Channel Mixup

The HKPilot32 (and other PixHawk variants) use a single “muxed” connection from the receiver to the AP.   What I was not ready for was that the channel assignments were all totally mixed up.  The throttle channel is now registering as roll (ie aileron), the roll as pitch (elevator), and the pitch as the throttle!  only the yaw channel remained.

Here’s the stock channels using the latest ArduPilot:Plane firmware (3.1.1):

Roll (Aileron) – Channel 1
Yaw (Rudder) – Channel 4
Pitch (Elevator) – Channel 2
Throttle  – Channel 3

The main issue here is that the channels are fixed on my transmitter (a Spektrum DX6i).  A quick check online shows that the consensus seems to be to change the assignment on the transmitter (oh boy) and not on the AP.  At any rate, this is not viable for me right now.. so I have to implement it on the plane.

The correct parameters to change in either AP Planner or Mission Planner are:  RCMAP_YAW, RCMAP_ROLL, RCMAP_THROTTLE and RCMAP_PITCH.

While these parameters are visible in both applications, for some reason I cant save it with AP Planner and the channels refuse to be reassigned.  The following worked with Mission Planner (v1.3.11):

Roll (Aileron) RCMAP_ROLL – Channel 2
Yaw (Rudder) RCMAP_YAW – Channel 4
Pitch (Elevator) RCMAP_PITCH – Channel 3
Throttle  RCMAP_THROTTLE – Channel 1

Note that this is only for the hardware combination above and may be different in other systems so a little trial and error may be required. Also, while available, changing these settings are not recommended for APM2.5/2.6.

Configuring RC5808 5.8Ghz 8-Channel Video Receiver for FPV

The RC 5808  is a simple 12v, 8 channel video receiver with a  single Video output for a monitor or goggles.  I’ve had mine for over a year and I’m completely happy with it.

RC 5808 Receiver
RC 5808 Receiver

The following channels and its frequencies are supported:

CH1 5.705 GHz
CH2 5.685 GHz
CH3 5.665 GHz
CH4 5.645 GHz
CH5 5.885 GHz
CH6 5.905 GHz
CH7 5.925 GHz
CH8 5.945 GHz

In order to change the frequencies, change the pin positions found on top of the receiver:

RC 5808 Receiver
Figure 1: RC 5808 Receiver Channel Assignment

The pin combination assignment to change the channel is found at the back of the receiver:

RC 5808 Receiver
Figure 2: RC 5808 Receiver Channel Pins

To change the channels, position the pin to closed or blacked out half.  For example, figure 1 above, is set to use channel 8 (with reference to figure 2).